It is known to install fuel injectors in an injector bore of an engine head using a C-clip and an alignment ring in a substantially rigid assembly. The C-clip captures the alignment ring to the fuel injector. It is known for the C-clip to be a split ring fitted over a bump on the fuel injector body to retain the alignment ring on the fuel injector. The alignment ring includes an angled surface that cooperates with an angled surface on the fuel injector to keep the injector in a vertical position within the injector bore, which in turn helps to ensure that a seal at the injector tip works properly. The C-clip outer edge interferes with the inner edge of the alignment ring, and the inner edge of the C-clip interferes with a protrusion on the fuel injector body. The C-clip provides a rigid installation system of the C-clip, the alignment ring and the injector the injector bore of the engine head.
C-clip and alignment ring installations of fuel injectors have worked well from a fuel system performance perspective; however, the installations are not without disadvantages. The rigid alignment allows no movement over the entire engine load range, which results in poor sound performance at engine idle conditions. Allowing slight movement under idle or low load conditions can improve sound performance. However, it is desirable for more limited movement at high load engine operating conditions for injector tip seal performance.
Accordingly, it is desirable to provide a two-phase spring useful for installing a high-pressure fuel injector in an engine to provide limited, controlled movement of the injector at low engine speeds with stiffer performance of the spring at high engine speeds.